Spas with reservation required

Saratoga Springs, New York

Historic 1935 bathhouse in Saratoga Springs offering mineral water soaks and massages in original tubs, reservation only, moderate pricing.

Mexico City, Quintana Roo

A Japanese-style hotel spa in Mexico City's Cuauhtémoc district with tatami suites, outdoor onsen baths and a $2,080 day pass for couples.

Ras Al Khaimah

A luxury hotel spa on Hayat Island in Ras Al Khaimah with pearl-shaped treatment rooms and a Turkish Hammam, open daily 10am–7pm by reservation.

Milford, Ohio

A small, adults-only day spa in Historic Old Milford with a salt room, massage room and red light therapy, booked by reservation.

Indianapolis, Indiana

A moderate-priced day spa in northwest Indianapolis offering float therapy, salt room sessions, infrared sauna, cold plunge and foot detox, closed Mondays.

Santa Fe, New Mexico

A small Santa Fe day spa centered on a halotherapy salt room, with sauna and ionic foot detox add-ons, booked by reservation only.

Asheville, North Carolina

A Japanese-inspired destination spa on a mountainside outside downtown Asheville, built around private outdoor salt hydrotherapy tubs and massage.

Sierraville, California

A non-profit hot springs retreat near Lake Tahoe with natural spring pools, reservation-only day and evening soaks, camping and rooms, closed Mondays and

Kyoto

Hotel spa in Kyoto's Higashiyama Ward with a day pass for pool, bathhouse, sauna and gym, plus treatment suites and couples options.

Sopot, Pomerania

A medical resort spa in Sopot built around local brine and mud treatments, open to hotel guests by reservation rather than day visitors.

Santa Barbara, California

A downtown Santa Barbara day spa built around a private infrared sauna, salt room, cold plunge and a sound-and-light meditation pod, booked by appointment.

Austin, Texas

Adults-only hotel spa at the Fairmont Austin with nine treatment rooms, a hydrotherapy circuit, sauna and cold plunge, open daily with day passes available.

Carmel-by-the-Sea, California

Resort spa at Carmel Valley Ranch with 12 treatment rooms, private terraces, a saltwater pool and infinity hot tub, open to adults by reservation.

San Diego, California

Adults-only day spa at Mission Bay Resort with massage, facials, Himalayan salt treatments and couples suites; walk-ins and day passes welcome.

Palm Springs, California

Hotel spa at the Renaissance Esmeralda in Indian Wells offering desert-inspired treatments, a recovery lounge, steam rooms and day passes, adults only.

Nashville, Tennessee

A Berry Hill day spa in Nashville offering massage, facials, body treatments and a sauna pod/salt room, open Tuesday through Saturday.

Piešťany, Trnava Region

Spa Irma on Piešťany's spa island offers historic mud and mirror thermal pools, a hydrotherapy circuit and a 60-treatment medical spa menu, adults only.

Los Angeles, California

A Westlake day spa built around themed sauna rooms—salt, gold, Loess soil, Elvan stone, forest and ice—plus a waterfall feature and garden.

Palm Springs, California

Adults-only hotel spa at Tommy Bahama Miramonte in Indian Wells with 15 treatments, eucalyptus steam rooms, a hydrotherapy jacuzzi and saltwater pool.

Napa Valley, California

Adults-only resort spa built into a wine cave in Napa, with a vineyard-view pool, sauna, steam room and hot tub; reservations required.

Essaouira, Marrakesh-Safi

A budget hammam and day spa in Essaouira's medina offering scrub treatments, massages, hair and nail services, open daily 10am-8pm.

Austin, Texas

A fifth-floor hotel spa inside JW Marriott Austin with eight treatments, a heated rooftop pool and a 16-plus minimum age.

Naples, Florida

Upscale day spa in Naples offering infrared sauna, massage, facials and foot detox, with a $230 signature massage and couples packages.

Jackson Hole, Wyoming

Resort spa at Teton Village with pools, soaking tubs, a rooftop hot tub, and facials built for Jackson Hole's dry alpine air.